Refrigeration apparatus including defrosting means



s- 1947- R. E, TOBEY 2,426,578

REFRIGERATION APPARATUS INCLUDING DEFROSTING MEANS Filed Nov. 5, 194:5 2sheets-sheet 2 ..FIG.2

INVENTOR Reyna/10%: Toqy BY ATTOREEY PM M ze, 1941, A,

REFRIGERATION APPARATUS INCLUDING DEEBOSTING MEANS Raymond E, Tobey,Springfield, Mass., assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 5,194:, Serial No. 509,058

This invention'relates to refrigeration apparatus and more particularlyto a means for defrosting an evaporator. n

It is an object of the invention to .provide novel means for regulatingthe refrigeration of an evaporator, I

Another object of the invention is to provide novel means -for renderingone evaporator of a plurality of evaporators supplied by a commonrefrigerant supplying apparatus inactive without interfering with therefrigeration or the other evaporators;

A further object of the invention is to stop the flow. of liquidrefrigerant toan evaporator of a plurality of evaporators, forming apart of a hermetically-sealed system, without introducing valves intothe system and without affecting the flow of liquid refrigerant to theremainder of the evaporators.

o A still, further object of the invention is to provide means whichpermit defrosting of one evaporator of a plurality of evaporators servedby common refrigerant circulation apparatus without affecting theoperation of the remaining evaporators.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawing, forming a. part of this application, in which:

F g. l is a sectional view of a mechanical refrigerator embodying theinvention and showing a schematic arrangement of the refrigerantpassages and the electric wiring. The .view is taken on line II of Fig.2;

Fig. 2 is a view of the food storage compartment of the refrigerator ofFig. 1 with the doors of the food storage compartment and the frozen.

food compartment removed, and the refrigerant passages shownschematically; and. r

Fig. 3 is a view, with parts broken away. of the refrigerant regulatingchamber of this invention with the regulating cylinder in the lowerposition. a

Fig. 4 is a vertical sectional view of the refrigerant regulatingchamber with the regulating cylinder in the upper position.

Referring now to the drawings for a detail description of the invention,the reference numeral l6 designates a refrigerator cabinet having an fordriving the same.

. 2 located in the lower portion of the food storage compartment l2. 7 N

The food storage compartment comprises an inner metal liner l8 and anouter metal shell 26 spaced from the inner liner l8. The inner liner [6is coated on the inner and outer sides with vitreous enamel. Thermalinsulating material 22 is positioned between the metal liner II and themetal shell- 20. The food storage compartment I2 is provided with anaccess opening and a door 24 for closing the same. A separate door "isprovided for the frozen food receptacle l6.

The food storage compartment i2 is maintained at an average temperatureof about 40 F. by a refrigerant carrying tube 26 secured to the metalliner is. The tube 26 is shown located on the inner side of the metallinerl8 for the sake of clearness. In actual practice, it is located onthe outer side thereof embedded in the thermal insulation 22. The frozenfood receptacle I6 is maintained at an average temperature of about 25'F. by a second refrigerant carrying tube 28 which is coiled around andbrazed to the receptacle l6. The tubes 26 and 28 are connected in seriesand a suction tube 36 is connected to one end of the tube 28 to withdrawrefrigerant vapor therefrom.

The tube 30 conducts the refrigerant vapor to a hermetically-sealedrefrigerant liquefying apparatus, comprising a sealed casing 32 whichcontains a refrigerant compressor and a motor The compressor and themotor are not shown in the drawings. The compressed refrigerant vaporpasses through a tube 34 to a refrigerant condenser 36, wherein therefrigerant vapor is cooled and condensed into a liquid. The condenser36 is cooled by a current of air drawn therethrough by a motor-drivenfan 38.

A chamber 42, forming a part of thisinvention, is located in the thermalinsulating material 22 of the rear wall of the food storage compartmentl2. The chamber 42 is formed of brass or other non magnetic material.The liquid refrigerant is conducted by a capillary tube 46 from thecondenser 36 to the upper portion of the chamber insulated food storagecompartment. II in the upper portion and a machine compartment It in gthe lower portion of the cabinet. The food storage compartment l2is'provided with a drain tube 15. A metal receptacle ii for frozen foodsis 42. The capillary tube 40- aflords such impedance to the flow ofrefrigerant that substantially no liquid refrigerant is retained inthecondenser 36 during normal operation. The chamber 42 has an opening 44approximately midway between its top and bottom, and a tube 46communicates with the' opening 44 to conduct the refrigerant liquidflowing from said opening 44 to the tube 26. The chamber 42 iscontinuously filled with refrigerant liquid to the level of the opening44 and with refrigerant vapor above said opening. The refrigerant liquidin the chamber 42 is comparatively inactive because the thermalinsulation surrounding the chamber 42 prevents heat from being conductedto the liquid and vaporizing it.

A cylinder 48 of iron or other magnetic material is located in thechamber 42 and normally occupies substantially all of the portion of thechamber lying below the level of the opening IL- An electric winding IIis placed around the upper portion of the chamber 42 and when energizedraises the cylinder 48 and retains it in the upper portion of thechamber 42. The chamber 42, thereupon, will fill up with refrigerantliquid to the level of opening 44: Theelectric winding ill on thechamber 42 is energized from sup- I ply lines 52 and 54 through leads 58and 58. A switch 60 is located in series in the lead 56.

The temperature of the food storage compartment I2 is controlled byatheimostat 64 comprising a bulb 88 containing a volatile refrigerantliquid. The bulb 68 is in thermal contact with the metal liner II andconnects with a Sylphon bellows 88 through a tube 1'0. TheSylphonbellowsfl opens and closes a switch 12 located in a lead 14 whichtogether with lead 16 supplies electrical energy from the supply lines52 and 54 to the compressor located in the hous-- ing 32. Thetemperature of the food storage form, it will be obvious to thoseskilled in the art that it is not so limited, but is susceptible ofvarious changes and modifications without departing from the spiritthereof, and I desire,

' therefore, that only such limitations shall be from said compressor, atube connected to concompartment I! will thus be maintainedsubstantially constant regardless of the position of the cylinder 48.

Operation During normal operation, the switch 60 is open ductrefrigerant liquid from said condenser to said first evaporator, athermostatic control for said compressor to maintain said first chamberat an above-freezing temperature, and means for providing the effect ofselectively varying the refrigerant charge -of the refrigerator to theextent of supplying liquid refrigerant either sufficlent for both ofsaid evaporators or sufficient for qnly said first evaporator, saidsecond evaporator and second chamber being in such heat-transferrelation and the suction of said compressor being' such that said secondchamber is maintained at below-freezing temperatures when saidrefrigerant charge is sufllcient for both evaporators.

" 2. A refrigerator comprising first and second evaporators connected inseries, first and second and the refrigerating apparatus supplies boththe tubes 26 and 20 with refrigerant liquid, and only the tube 28 andfrozen food recept'acle It will accumulate frost. If it is desired todefrost the frozen food receptacle IS, the switch 60 is closed. Thisenergizes the winding 50 on the chamber 42 and elevates the cylinder 48.Refrigerant liquid of the system will then accumulate in the chamber 42to the level of opening 44, and the chamber 42 thereby abstracts aquantity of refrigerant -liquid from the system and renders theabstracted liquid inactive. The active refrigerant liquid remaining inthe system is sufil cient to refrigerate only the food storagecompartment I! because the refrigerant liquid is completely vaporized inthe tube zfi'so that only refrigerant vapor passes through the tube 28.The vapor, however, is at the temperature prevailing in the tube 26 andfurthermore does not have the heat absorbing capacity of the refrigerantliquid. The frozen food receptacle It will, thereupon, increase intemperature to that of the food storage compartment l2, the frost on thefrozen food receptacle 8 will melt, and the defrost water will fiow outthrough the drain tube l5.

It will be apparent from the above that this invention providesapparatus for defrosting one evaporator of a plurality of evaporatorssupplied by a common refrigerant supplying apparatus. The invention alsoprovides a means for varying the amount of effective refrigerant in aclosed refrigerating system. It will be further apparent that theapparatus of this invention does not introduce valves into ahermetically-sealed refrigstorage chambers in heat-transfer relationwith said first and second evaporators respectively, a compressor forwithdrawing refrigerant vapor, the suction side of said compressor beingconnected to said second evaporator at a point remote from theconnection of said second evaporator to said first evaporator, acondenser receiving compressed refrigerant vapor from said compressor, atube connected to conduct refrigerant liquid from said condenser to saidfirst evaporator, thermostatic means controlling said compressor tomaintain said first chamber at an above-freezing temperature, thesuction of said compressor beingof such degree and the heat-transferrelation between said second evaporator and said second chamber being somuch more effective than the heat-transfer relation between said firstevaporator and said first chamher as to cause said second chamber to bemaintained at a below-freezing temperature when said first chamber ismaintained at said above-' freezing temperature and said first andsecond evaporators are supplied with liquid refrigerant by saidcondenser and tube, and means for providing' the effect of selectivelyvarying the refrigerant charge of the refrigerator to the extent ofsupplying liquid refrigerant either suflicient for both of saidevaporators or sufficient for only said first evaporator.

RAYMOND E. TOBEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number 2,133,952- Buchanan a Oct. 25,- 1938

